In petroleum refineries, bitumen generated as a bottom/residue product in distillation columns after treatment of the crude oil is widely used in asphalt-coated roads as a binding raw material as well as its areas of usage such as waterproofing.
In asphalt-coated roads achieved with the use of bitumen which is a refinery product, thermal cracks, cracks resulting from fatigue and rutting problems are experienced over time, depending on the area of use and climate conditions. Depending on the growing vehicle density, such impairments also tend to increase. However, with the bitumen compositions used in the prior art, in areas where high vehicle density is seen or extremely hot/cold climate conditions prevail, said problems experienced in highways may not be solved.
In addition to the said problems, it is necessary to store carbon based crude oil derivatives and process by-products/residues in petroleum refineries so as to render them harmless to the environment or to develop methods for economic use thereof.
Based on the prior art, various additives are used and modified bitumen compositions are developed, in order to increase the resistance and performance of the bitumen compositions to avoid said problems. In the modified bitumen compositions according to the present invention, resistance of the binding bitumen and thus asphalt coatings is increased by addition of viscosity reducing fillers such as sulphure and ash, and mainly polymer, and different additives that induce cross-linking.
The state-of-art document U.S. Pat. No. 5,807,478A discloses bitumen modification using ash derived from bitumen petrocoke. In the said method, vanadium and nickel containing ash is added to the bitumen to lower the viscosity and specific gravity of the bitumen whereby it is rendered pipelineable. Here, the ash is added to the bitumen in an amount of about 5 to 25 wt. %. Therefore, the technical problem to be solved by U.S. Pat. No. 5,807,478A is to change the viscosity and specific gravity of the bitumen so as to render it pipelineable, wherein no mention is made to increase the resistance of bitumen.
In the state-of-art document U.S. Pat. No. 5,449,401A, it is disclosed that with the addition of fly ash in combination with the aggregate into hot-mix asphalt, the resistance of the asphalt to cracks and potholes is enhanced. In the said fly ash, calcium, magnesium, arsenic, boron, cadmium, chromium, cobalt, copper, iron, lead, manganese, molybdenum, nickel, vanadium, zinc, selenium, strontium, aluminum and zirconium are present. Added fly ash improves mechanical properties of asphalt such as tensile force, flexibility etc. and reduces costs with respect to the amount of use. However, since some materials in the fly ash are toxic, the production method of the modified bitumen disclosed in U.S. Pat. No. 5,449,401A becomes unsafe especially for the workers.
U.S. Pat. No. 8,062,413 B1 uses aggregate and high carbon content fly ash in order to increase the performance of an asphalt mixture. It is known that fly ash in the amount of 3% to 10% along with bitumen and aggregate increases the resistance and stability against crack formation in asphalt. However, use of fly ash resulting from combustion of fuels in U.S. Pat. No. 5,449,401A and U.S. Pat. No. 8,062,413B1 causes air pollution and emissions of pollutant combustion. Furthermore, fly ash used in similar patent documents as U.S. Pat. No. 5,449,401 A and U.S. Pat. No. 8,062,413 B1 is utilized in combination with aggregate in asphalt mixture, not a bitumen additive.
In the literature, some of the modifications to improve properties of the asphalt coatings may be performed on asphalt composition, and others may be performed on bitumen compositions. In accordance with EN 13108-4 standard, the amount of bitumen used in asphalt composition is 4% to 11%. Although the amount of bitumen used in asphalt appears to be low according to the standard, it is one of the most important factors that directly and dominantly affect the properties of asphalt.
Finally, in the state-of-art, there is no product or method that increases performance grading of bitumen by using petrocoke, a by-product of a refinery process, and extract, a base oil unit by-product, and allows obtaining modified bitumen and high quality asphalt.